ES2961262T3 - Generator set to generate an alternating current - Google Patents

Abstract

The present invention relates to a generating set (1) for generating alternating current, comprising a primary power unit (2) and an alternating current generator (3) rotatably coupled to the primary power unit (2), which is configured to generate a primary energy provided by the primary energy unit (2). into electrical energy, and a switchable secondary power unit (4), which is designed in such a way that the power generated by the alternating current generator (3) increases when turning on the secondary power unit (4). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Generator set to generate an alternating current

Technical field

The present invention relates to a generating set for generating alternating current.

State of the art

Conventional generating sets are generally made up of an internal combustion engine and a generator, the internal combustion engine being coupled by means of a gear or directly to the electric generator, generally an independently excited synchronous machine.

In this sense, the requirements for the frequency of the alternating current network are determined by standards that define, for example, also the permissible frequency deviation. In an alternating current network with several sources, the power distribution is regulated by frequency. The higher the frequency, the greater the proportional power contribution.

The objective in many cases is to keep the relative power contribution of a generator constant as much as possible at different operating points. So that the frequency does not go out of the admissible tolerance band, even in the event of a load with a jump in power, the internal combustion engine must have adjustment reserves and rapid regulation. The mass inertia of the generator set also helps keep the frequency constant in the event of a load jump.

Internal combustion engines often lack the necessary tuning dynamics, so even when a tuning reserve exists, larger engines are used to provide the necessary mass inertia. This leads to the use of internal combustion engines whose rated power is significantly higher than the rated power of the generator. Due to this, in many cases the exhaust gas temperature necessary for perfect exhaust gas post-treatment is not reached. As a result, maintenance costs increase. In addition, more complex and/or additional exhaust gas purification must be provided. This leads to high costs for the internal combustion engine and the exhaust system.

Document EP 2 251 953 A2 shows a current generation system with a generating set comprising an internal combustion engine and a variable speed generator coupled thereto, which is configured to generate electrical power. Additionally, an auxiliary generator/engine set is connected with the generator.

EP 3351 472 A2 shows a device for providing electrical energy for an electrical consumer and/or for charging a battery on a ship.

Document DE 102005000998 A1 shows an isolated alternating current network with a generator that feeds the isolated network, driven by an internal combustion engine and a solar current source that feeds its energy simultaneously to the isolated network, starting the solar current. of this a direct current motor that drives the alternating current generator through a mechanical clutch together with the internal combustion engine.

Description of the invention

Starting from the known state of the art, an objective of the present invention is to provide an improved generator set for generating an alternating current.

This objective is achieved by means of a generating set to generate an alternating current with the characteristics of claim 1. Advantageous improvements emerge from the dependent claims, the description and the figures.

Correspondingly, a generating set for generating an alternating current is proposed, comprising a primary power unit and an alternating current generator that is rotatably coupled to the primary power unit, which is configured to convert a primary power provided by the unit of primary power in an electrical power. The generating set is further characterized by a connectable secondary power unit, which is configured in such a way that the power generated by the alternating current generator increases when the secondary power unit is connected.

Since a connectable secondary power unit is provided, which is configured in such a way that the power generated by the alternating current generator increases when the secondary power unit is connected, an additional power demand can be temporarily covered, which exceeds the power that can be supplied by the rated power of the internal combustion engine, without having to provide power reserves in the internal combustion engine, which would eventually lead to an internal combustion engine whose rated power would be significantly higher than the rated power of the generator. By contrast, thanks to the switchable secondary power unit, an almost optimal configuration between the internal combustion engine and the AC generator can be achieved for continuous operation, in particular for operation of the AC generator at its rated power.

Therefore, in the intended continuous operation of the primary power unit, it may operate close to its rated power or even at the rated power. Accordingly, an exhaust gas temperature necessary for the best possible exhaust gas aftertreatment provided for this primary power unit can be achieved. Thanks to this, the maintenance costs of the primary power unit can be kept low. Furthermore, the exhaust gas aftertreatment can have a simple structure and/or an additional and/or complex exhaust gas aftertreatment unit, which would otherwise have to be provided, can be dispensed with.

Preferably, the secondary power unit is configured to be able to be connected at least temporarily.

According to a preferred embodiment, the power of the AC generator corresponds to a power generated by a primary rated power input supplied to the AC generator by the primary power unit. Thanks to this it is possible to operate the primary power unit close to its optimal operating point.

Tests have shown that it is especially advantageous for the primary power unit to be an internal combustion engine.

Advantageously, the alternating current generator is an independently excited synchronous machine.

According to the invention, the secondary power unit has an electric motor, preferably an asynchronous machine or a reluctance motor or a "switched reluctance motor" (SRM), and a secondary accumulator. energy that is in contact with the electric motor, preferably a battery, in particular a lithium-ion battery, or a capacitor, in particular an electrolytic capacitor, or a supercapacitor, the electric motor according to the invention being rotatably coupled to an input shaft of the alternating current generator. Thanks to the electric motor it is possible to provide additional mechanical power, in particular additional torque, in the alternating current generator in addition to the power provided by the primary power unit. It has been shown that an electric motor, in particular if configured as an asynchronous machine or as a reluctance motor, has a particularly good overload capacity as well as very good control dynamics. Furthermore, an electric motor, configured in particular as an asynchronous machine or reluctance motor, has few losses in standby operation, which are generally negligible. Alternatively, the electric motor can also be configured as a permanently excited synchronous machine, if the permanently occurring iron losses are acceptable.

The establishment of electrical contact between the electric motor and the secondary energy accumulator optionally comprises a current converter, preferably a frequency converter, the current converter acting as an adaptation element between the secondary energy accumulator and the electric motor. , so that the energy provided by the secondary energy accumulator is converted or transformed into a form suitable for the operation of the electric motor in its respective embodiment.

According to another preferred embodiment, an output shaft of the primary power unit is directly rotatably connected to an input shaft of the alternating current generator. Alternatively, the output shaft of the primary power unit may be rotatably geared to the input shaft of the AC generator.

According to another preferred embodiment, an output shaft of the secondary power unit is directly rotatably connected to an input shaft of the alternating current generator. Alternatively, the output shaft of the secondary power unit may be rotatably geared to the input shaft of the AC generator.

Preferably, the secondary power unit can be decoupled from the AC generator and/or the secondary power unit can be configured in a torqueless connectable manner.

Preferably, the secondary power unit may be configured such that an electric motor of the secondary power unit is configured such that it can function as a generator. Thanks to this, an energy accumulator of the secondary power unit can be charged by the generator operation of the electric motor of the secondary power unit. The torque necessary for operation of the generator can also be provided by the primary power unit and transmitted by the alternating current generator or by a continuous input shaft of the alternating current generator.

Furthermore, the current converter of the electrical contact establishment can be configured in such a way that the energy generated by the electric motor during the operation of the generator can be converted into a form suitable for charging the secondary energy accumulator of the secondary power unit. In other words, the current converter or converter may be configured such that it can operate bidirectionally. Alternatively, another converter may also be provided in the electrical contact establishment and/or another converter, preferably a rectifier, is provided separately from the electrical contact establishment.

The electric motor of the secondary power unit may be configured to be able to be switched on without torque. As long as the primary power unit is capable of covering by itself the power demand requested by the generating set, for example by a consumer, the electric motor of the secondary power unit can be connected without torque.

In particular, taking into account a desired torque addition of a torque provided by the primary power unit and a torque provided by the secondary power unit, it has proven to be advantageous to arrange the primary power unit on a first side of the current generator. alternating with respect to the alternating current generator and arranging the secondary power unit on a second side of the alternating current generator, opposite to the first side of the alternating current generator.

Alternatively, the primary power unit and the secondary power unit may also be arranged together on one side of the AC generator, if the output shafts of the primary power unit and the secondary power unit allow for an addition of torque. .

According to the invention, the primary power unit has a speed regulator and the secondary power unit has a speed regulator.

To achieve simple decentralized control/regulation of the secondary machine, the activity of the secondary power unit can additionally be determined by its own tolerance band.

Consequently, the activity of the primary power unit can also be determined by its own tolerance band.

According to the invention, a theoretical speed is fed to the speed regulator of the secondary power unit which is lower, preferably slightly lower than the theoretical speed of the primary power unit. In this regard, the theoretical value of the secondary power unit is preferably located in the predetermined tolerance band for the secondary power unit.

Preferably, the regulation structure of the primary power unit and/or the secondary power unit is made with two stages, an internal speed regulator being preferably subordinated to an external speed regulator. In this sense, the speed regulator can supply predetermined values for the torque regulator, the predetermined values being preferably limited to positive torque values. Thanks to this it can be achieved that the secondary power unit normally cannot work against the speed regulator of the primary power unit.

It has been shown that in case of optional use of a pure P amplifier, additional safety can be achieved. By providing the amplifier P, it can be achieved that the set torque increases with the regulation deviation, that is, the closer the speed is to the theoretical value of the secondary power unit, the lower the torque will be.

According to another preferred embodiment, the primary power unit comprises a speed regulator with connectable and disconnectable negative torque and/or the secondary power unit comprises a speed regulator with connectable and disconnectable negative torque. Preferably, provision is made to control/regulate the connection or disconnection of the negative torque according to the energy content of the energy accumulator of the secondary power unit.

In particular, in the case where the energy accumulator of the secondary power unit has a small capacity, so that the voltage changes significantly when the secondary machine or secondary power unit is used, this voltage can be used as a criterion for activate or deactivate a negative torque. Preferably, a negative torque is enabled when the voltage of the energy accumulator falls below a first limit value determined for this purpose. Furthermore, the enabling of the negative torque can be overridden again if another limit value, which is higher than the first limit value, is exceeded. Thanks to this, a hysteresis can be provided that allows stability with respect to the charging function of the accumulator.

According to a preferred alternative configuration, the control/regulation of the connection or disconnection of the negative torque can also be based on another quantity, preferably a charge of the energy accumulator. In particular, this may be advantageous if the capacity of the energy accumulator is so large that the voltage does not show significant changes during power supply. To use the load as a control/regulating quantity, the accumulated current can be integrated with respect to time. Analogously to control/regulation by the energy storage voltage, also when the energy storage load is used as a control variable/regulation variable, the negative torque can be enabled or switched on when the value falls below a certain value. predetermined, such as an integral value of the accumulated current, and disconnect again when the value exceeds another predetermined value, which is greater than the first predetermined value mentioned above.

Preferably, another regulator can be provided for the control/regulation of the voltage amplitude. When using a separate excitation synchronous generator, this can optionally be done by excitation tracking.

According to another preferred embodiment, the secondary power unit, preferably an electric motor of the secondary power unit, is configured in such a way that its torque, preferably its nominal torque, is greater than a starting torque of the power unit. primary, preferably greater than the starting torque plus the mechanical losses present in the prescribed system. In other words, the secondary power unit may be configured to provide a torque that is greater than the starting torque and mechanical losses of the generator set. Thanks to this, it may be possible to start the generating set using the secondary power unit, or at least promote the starting of the generating set using a starter.

According to another preferred embodiment, the secondary power unit comprises a secondary energy accumulator, preferably a battery, in particular a lithium-ion battery, or a capacitor, in particular an electrolytic capacitor or a supercapacitor, and an inverter, preferably an externally controlled inverter. Preferably, an output cable of the alternating current generator and an output cable of the inverter are connected to each other, preferably being configured in a pluggable and detachable manner. Thanks to this, additional power can be supplied directly from the energy store via the inverter to the power generated by the AC generator by connecting the secondary power unit. Thanks to this, the primary power unit can be discharged and it can continue operating at the point for which it is designed.

According to another preferred embodiment, the inverter of the secondary power unit is an inverter that operates bidirectionally. Thanks to this, energy can be provided by the alternating current generator to (re)charge the secondary energy accumulator in normal operation and fed by the inverter that operates bidirectionally to the secondary energy accumulator. Alternatively, it may also be provided to provide an additional rectifier, by means of which the secondary energy accumulator can be charged with the alternating current generated by the alternating current generator.

In another preferred embodiment, it may be provided that the secondary energy accumulator can be charged by connecting to an electrical network. For this purpose, the secondary energy accumulator preferably has a corresponding connection unit.

Brief description of the figures

Other preferred embodiments of the invention are explained in more detail by the following description of the figures. In this regard they show:

Figure 1 schematically shows a generating set for generating an alternating current according to a first embodiment;

Figure 2 schematically shows a generating set for generating alternating current according to another embodiment; and

Figure 3 schematically shows a generating set for generating an alternating current according to another embodiment.

Detailed description of preferred embodiments

Preferred embodiment examples are described below with the help of the figures. In this regard, elements that are the same, similar or that act in the same way in the different figures receive identical references and a repeated description of these elements is partially omitted to avoid redundancies.

Figure 1 schematically shows a generating set 1 for generating an alternating current according to a first embodiment. The generating set 1 comprises a primary power unit 2 in the form of an internal combustion engine, in the present case a diesel engine, and an alternating current generator 3, which is rotatably coupled to the primary power unit 2, in the present case in the form of an independent excitation synchronous machine, which is configured to convert a primary power provided by the primary power unit 2 into an electrical power. The generating set 1 further has a connectable secondary power unit 4, which is configured in such a way that the power generated by the alternating current generator 3 can be temporarily increased by connecting the secondary power unit 4.

In this sense, the power of the alternating current generator corresponds to a power generated by a primary rated power input supplied to the alternating current generator by the primary power unit.

The secondary power unit 4 has an electric motor 40, in the present case an asynchronous machine, and a secondary energy accumulator 41 which is in contact with the electric motor 40, for example in the form of a battery, in particular a battery of lithium ions. or in the form of a capacitor, optionally an electrolytic capacitor or a supercapacitor. The establishment of electrical contact between the electric motor 40 and the secondary energy accumulator 41 comprises a bidirectionally operating converter (not shown), which converts the energy provided by the secondary energy accumulator 41 into the form suitable for the operation of the electric motor 40 and vice versa.

The electric motor 40 is rotatably coupled to an input shaft 30' of the alternating current generator 3. Thanks to the electric motor 40 it is possible to provide additional mechanical power, in particular additional torque, to the alternating current generator 3, in addition to the power provided by primary power unit 2.

Alternatively, the electric motor 40 may also be configured as a reluctance motor or "switched reluctance motor" (SRM). Furthermore, the output shaft 42 of the secondary power unit 4 may be connected by a gear (not shown) rotatably with the input shaft 30' of the alternating current generator 3.

An output shaft 20 of the primary power unit 2 is rotatably connected by a gear 22 to an input shaft 30 of the alternating current generator 3. Alternatively, the output shaft 20 may also be rotatably coupled directly to the input tree 30.

The electric motor 40 is configured to be able to be decoupled from the alternating current generator 3. In addition, the electric motor 40 can also function as a generator in order to charge the secondary energy accumulator 41, when it is not necessary to provide additional power by the power unit. secondary 4.

As long as the primary power unit 2 is capable of covering by itself the power demand requested by the generating set 1, for example by a consumer, and the secondary energy accumulator 41, the electric motor 40 of the unit does not have to be loaded. Secondary power 4 can be connected without pair.

In the present case, with respect to the alternating current generator 3, the primary power unit 2 is arranged on a first side of the alternating current generator 3 and the secondary power unit 4 is arranged on a second side of the alternating current generator 3, opposite the first side.

Alternatively, the primary power unit 2 and the secondary power unit 4 may also be arranged together on one side of the alternating current generator 3.

In the present case, the primary power unit 2 and the secondary power unit 4 respectively have a speed regulator. Furthermore, the primary power unit 2 and the secondary power unit 4 are respectively assigned their own tolerance band.

A setpoint value in the form of a setpoint speed, which is slightly below a setpoint value in the form of a setpoint speed of the primary power unit 2, is supplied to the speed regulator of the secondary power unit 4, although in the band default tolerance for secondary power unit 4.

The primary power unit 2 and the secondary power unit 4 respectively have a regulation structure realized with two stages, an internal speed regulator being respectively subordinated to an external speed regulator. Thanks to this, the speed regulator supplies the default values for the torque regulator, the default values according to this embodiment being optionally limited to positive torque values.

Furthermore, different speed threshold values are predetermined for the primary power unit 2 and the secondary power unit 4. This provides a hysteresis effect for the primary power unit 2 and the secondary power unit 4, which reduces or even completely eliminates the appearance of speed oscillations in the theoretical speed, which could appear by connecting and/or disconnecting the torque provided by the secondary power unit 4.

To provide additional safety, a pure P amplifier is used.

The speed regulator of the secondary power unit 4 is configured with a negative on and off torque. In the present case, the connection or disconnection of the negative torque is controlled/regulated based on the energy content of the secondary energy accumulator 41.

The electric motor 40 of the secondary power unit 4 is configured in such a way that it can provide a torque that is greater than a cumulative torque formed by the starting torque of the primary power unit 2 and the mechanical losses of the generator set 1. Thanks to this, the generating set 1 can be started by the secondary power unit 4.

Figure 2 schematically shows a generating set 1 for generating an alternating current according to another embodiment. The generating set 1 of Figure 2 essentially corresponds to the generating set of Figure 1, a rectifier 43 being further provided, by means of which the secondary energy accumulator 41 can be disconnectably connected to the output cable 32 of the alternating current generator. 3. Thanks to this, the secondary energy accumulator 41 can be charged by the rectifier 43, converting the alternating voltage provided by the alternating current generator 3 into a direct voltage.

Figure 3 schematically shows a generating set 1 for generating an alternating current according to another embodiment. Analogously to the embodiments of Figures 1 and 2, the generating set 1 has a primary power unit 2 in the form of an internal combustion engine, which is connected by a gear 22 with an alternating current generator 3.

As an alternative to the embodiments of Figures 1 and 2, the secondary power unit 4 in Figure 3 has a secondary energy accumulator 41, for example a battery, such as a lithium-ion battery, or a capacitor , for example an electrolytic capacitor or a supercapacitor, as well as an inverter 45, optionally in the form of an externally controlled inverter 45.

An output cable 44 of the inverter 45 is connected in a pluggable and detachable manner with the output cable 32 of the alternating current generator 3. To provide additional power in the output cable 32, the output cable 44 can be connected with the cable output 32. In this way, additional power is provided by the inverter 45 from the secondary energy accumulator 41.

Optionally, the inverter 45 can be configured as an inverter or converter that operates bidirectionally, so that in normal operation, the secondary energy accumulator 41 can be charged with the power provided on the output cable 32 by the alternating current generator 3. Alternatively, analogously to the configuration of Figure 2, a separate rectifier (not shown in Figure 3) may be provided to charge the secondary energy accumulator 41.

Reference List

1 Generator set

2 Primary power unit

20 Output shaft

22 Gear

3 AC generator

30, 30' Entry Tree

32 Outlet duct

4 Secondary power unit

40 Electric motor

41 Secondary energy accumulator

42 Output shaft

43 Rectifier

44 Outlet duct

45 Investor

Claims (11)

1. Generating set (1) for generating an alternating current, comprising a primary power unit (2), an alternating current generator (3) rotatably coupled to the primary power unit (2), which is configured to convert a primary power provided by the primary power unit (2) into an electrical power, and a connectable secondary power unit (4), which is configured in such a way that the power generated by the alternating current generator (3) is increased by connecting the secondary power unit (4), the secondary power unit (4) presenting an electric motor (40) and a secondary energy accumulator (41) that is in contact with the electric motor (40), the electric motor (40) being rotatably coupled to a shaft input (30') of the alternating current generator (3), the primary power unit (2) presenting a speed regulator and the secondary power unit (4) presenting a speed regulator, characterized by a theoretical speed is fed to the speed regulator of the secondary power unit (4) that is lower than the theoretical speed of the primary power unit (2). 2. Generating set (1) according to claim 1, characterized in that the nominal power of the alternating current generator (3) corresponds to a power generated by a primary nominal power input supplied to the alternating current generator (3) by the unit. primary power (2). 3. Generating set (1) according to claim 1 or 2, characterized in that the primary power unit (2) is an internal combustion engine and/or in that the alternating current generator (3) is an independently excited synchronous machine. . 4. Generating set (1) according to one of the preceding claims, characterized in that the electric motor (40) is an asynchronous machine or a reluctance motor, and/or the secondary energy accumulator (41) is a battery, in particular a lithium ion battery, or a capacitor, in particular an electrolytic capacitor or a supercapacitor. 5. Generating set (1) according to one of the preceding claims, characterized in that an output shaft (20) of the primary power unit (2) is directly rotatably connected to an input shaft (30) of the current generator. alternating current (3), or because the output shaft (20) of the primary power unit (2) is connected by means of a gear (22) in a rotary manner with the input shaft (30) of the alternating current generator (3). ). 6. Generating set (1) according to one of the preceding claims, characterized in that an output shaft (42) of the secondary power unit (4) is directly rotatably connected to an input shaft (30') of the generator. alternating current (3), or the output shaft (42) of the secondary power unit (4) is connected by a gear in a rotary manner with the input shaft (30') of the alternating current generator (3). 7. Generating set (1) according to one of the preceding claims, characterized in that the theoretical point of the secondary power unit (4) is located in a predetermined tolerance band for the secondary power unit (4). 8. Generating set (1) according to one of the preceding claims, characterized in that a regulation structure of the primary power unit (2) and/or a regulation structure of the secondary power unit (4) is made with two stages. , an internal speed regulator preferably being subordinated to an external speed regulator, the speed regulator preferably supplying predetermined values for the torque regulator, the predetermined values preferably being limited to positive torque values. 9. Generating set (1) according to one of the preceding claims, characterized in that the primary power unit (2) comprises a speed regulator with negative torque that can be connected and disconnected and/or the secondary power unit (4) comprises a speed regulator. speed with connectable and disconnectable negative torque, preferably a connection or disconnection of the negative torque can be controlled/regulated according to the energy content of the secondary energy accumulator (41) of the secondary power unit (4). 10. Generator set (1) according to one of the preceding claims, characterized in that the secondary power unit (4) is configured to provide a torque that is greater than a starting torque of the primary power unit (1) and the losses mechanics of the generating set (1). 11. Generating set (1) according to claim 1 or 2, characterized in that the secondary power unit (4) comprises the secondary energy accumulator (41), preferably a battery, in particular a lithium ion battery, or a capacitor , in particular an electrolytic capacitor or a supercapacitor, and an inverter (45), preferably an externally controlled inverter (45).